204 CLINICAL BACTERIOLOGY AND H^EMATOLOGY 



cells. The most important are methylene blue, methyl green, 

 and toluidin. Ordinary basic fuchsin used in staining the tubercle 

 bacillus belongs to this group, as do haematoxylin, carmine, etc. 



We shall describe three methods of staining, and these are 

 sufficient for all purposes of diagnosis. They are : (i) Ehrlich's 

 method with his triacid stain ; (2) Jenner's method ; and 

 (3) eosin and methylene used separately. Of these, the second 

 method is the simplest, and all that is necessary in the vast 

 majority of cases. The third method is an emergency one, for 

 use when Jenner's stain is not at hand : the first is now almost 

 obsolete, but occasionally useful when a study of the granulations 

 of the leucocytes is of importance. 



1. Ehrlich's stain consists of a mixture of acid fuchsin, orange 

 G, and methyl green dissolved in water, glycerin, and alcohol. 

 It is difficult to prepare, and should be purchased from a trust- 

 worthy maker. Its use is very simple. The film is fixed by 

 heat in the manner already described, and the stain is poured on 

 to it, and allowed to act for five minutes. The film is then 

 washed, dried with blotting-paper, and then by gentle heat, and 

 mounted in balsam. 



Nuclei are stained green, red blood-corpuscles orange, and 

 eosinophile granulations bright red. The small eosinophile 

 granulations which are present in the polymorphonuclear cells 

 (the neutrophile granulations of Ehrlich) are stained a purplish or 

 coppery colour. The basophile granulations are unstained. 



This stain is not suitable for the parasite of malaria, nor for 

 bacteria. 



2. Jenner's stain consists of a solution of a compound of eosin 

 and methylene blue in methyl alcohol. It must be bought 

 ready prepared. Nothing could be more simple than the way in 

 which it is used ; no preliminary fixation is necessary, the film 

 being allowed to dry and flooded with the stain. After a period 

 of from a minute and a half to three minutes, the stain is washed 

 off by waving the film to and fro in distilled or rain water for a 

 few seconds, and the specimen dried by blotting it between two 

 pieces of clean blotting or filter paper, allowed to get quite dry, 

 and mounted in balsam or cedar-oil, and the specimen dried and 

 mounted.* 



* It has been objected that Jenner's method does not always give good 

 results, and that the above is an insufi&cient account of the process. Provided 

 that the stain is good (Grubler's can always be relied on, and will keep for 



